1. Technical Field
The present invention relates to a vehicle safety apparatus, and particularly relates to a locking mechanism for a door which covers an opening through which an inflatable vehicle occupant restraint deploys.
2. Description of the Prior Art
It is known to inflate an air bag to restrain a vehicle occupant in the event of a vehicle collision. The air bag, prior to inflation, is stored in a part of the vehicle, such as in the instrument panel, the steering wheel or door of the vehicle. When the air bag is inflated, it is deployed through an opening in the part of the vehicle in which it is stored. A deployment door or cover or the like closes the opening and conceals and protects the stored air bag. When the air bag is inflated, the inflating air bag pushes the deployment door or cover open to allow the air bag to inflate into a position to restrain the vehicle occupant. As used hereinafter in this application, the term "deployment door" means any cover for an opening through which an air bag is deployed.
A deployment door typically forms a part of an air bag module which includes an air bag and a source of fluid for inflating the air bag. The deployment door is presented or exposed to the passenger compartment of the vehicle. A deployment door is typically made of a flexible material so as to be resilient or energy absorbent in the event of contact by a vehicle occupant.
An air bag module typically includes means for resisting opening of the deployment door except upon inflation of the air bag. Some known deployment doors have releasable fasteners or clips or other locking portions which resist movement of the door to an open condition except upon inflation of the air bag. Once such doors have been opened, however, it is possible to return the doors to a closed condition.
It is desirable that a deployment door not be returnable to a closed condition after opening. If the door cannot be returned to a closed condition after opening, then it will be evident to a vehicle occupant that the air bag has been deployed and that the air bag module should be replaced or otherwise serviced. This feature can also minimize the possibility of unauthorized opening of an air bag module.